1. Field of the Invention
The present invention relates to a shaft supporting structure in a compressor, in which a single-head piston is reciprocatable in a cylinder bore and a swash plate is tiltabley supported on a rotary shaft in crank chamber, and which controls the inclined angle of the swash plate based on the difference between pressure in a crank chamber and suction pressure.
2. Description of the Related Art
In general, compressor units used in automobiles, trucks and the like are used to supply compressed refrigerant gas to the vehicle's air conditioning system. To maintain air temperature inside the vehicle at a level comfortable for the vehicle's passengers, it is important to utilize a compressor whose displacement amount of the refrigerant gas is controllable. One known compressor of this type controls the inclined angle of a swash plate, tiltably supported on a rotary shaft, based on the difference between the pressure in a crank chamber and the suction pressure, and converts the rotational motion of the swash plate to the reciprocal linear motion of each piston.
In the conventional compressor, an electromagnetic clutch is provided between an external driving source, such as the vehicle's engine, and the rotary shaft of the compressor. Power transmission from the driving source to the rotary shaft is controlled by the ON/OFF action of this clutch. At the time the electromagnetic clutch is activated or deactivated, the clutch's action generates a shock generally detrimental not only to the compressor but also the overall driving comfort experienced by the vehicle's passengers. In addition, the integration of the clutch with the compressor increases the overall weight of the compressor.
The solve the above shortcomings, Japanese Unexamined Patent Publication No. 63-183277 discloses a variable displacement swash plate type compressor which does not employ an electromagnetic clutch for transmitting power from the external driving source to the compressor.
In this compressor, a pair of bearing members support a rotary shaft having a pulley secured thereto for power transmission from an external driving source. One of the bearing members is provided in a cylinder block while the other bearing member is provided in the housing which defines a crank chamber. The stable support of the rotary shaft results in the reduction of the vibration and noise of the compressor. This is achieved by increasing the distance between the bearing members. According to the structure in which the rotary shaft is supported in the housing, however, the distance between the bearing members cannot be increased unless the entire length of the compressor is increased.